Hide upload_path and upload_url_path from the UI for new installs

Description

Changing the upload_path and upload_url_path options are pretty dangerous. They have the potential to break quite a bit of things, not to mention they have the potential of simply not working.

In #19235, I was able to simplify wp_upload_dir() so the UPLOADS constant would again be 100% reliable. If you wanted to specify the exact location of your uploads dir, this is how you should do it, the same way you can move wp-content and other directories.

There's really no good reason to show upload_path or upload_url_path in the UI unless the values are other than the default (wp-content/uploads or '' for upload_path, and '' for upload_url_path). With that, most of a section disappears, leaving just year/month folder organization.

Hide upload_path and upload_url_path from the Media Settings screen, assuming they are both set to their default values.

These can be set on options.php, or the UPLOADS constant or the filters in wp_upload_dir() should be used. WordPress should aim to avoid UI options that require filesystem changes as well, not to mention requiring the user to convert between paths and URLs.